Pigment composition containing ATRP polymers

ABSTRACT

The present invention relates to a composition containing ATRP polymers and dispersible inorganic or organic pigment particles. The pigment composition is useful for preparing coating compositions, prints, images, inks or lacquers and other disperse systems.

[0001] The present invention relates to a composition containing ATRPpolymers and dispersible inorganic or organic pigment particles, aprocess for preparing the composition, a pigment dispersion containingATRP polymers and dispersible inorganic or organic pigment particles, aprocess for preparing the pigment dispersion and to the use of thepigment dispersion for preparing coatings, images, lacquers and others.

[0002] The present invention specifically relates to a pigmentcomposition containing ATRP (Atom Transfer Radical Polymerization)polymers characterized by a low polydispersity range, preferably apolydispersity range which is lower than 3, and an enhanced monomer topolymer conversion efficiency and predetermined molecular weights and toa pigment dispersion prepared from the pigment composition.

[0003] Dispersions containing pigments and polymer additives are used inan almost unlimited number of different technical applications, e.g. ascoating materials, printing inks, for coloring plastic materials,including fibers, glasses, or ceramic products, for formulations incosmetics, or for the preparation of paint systems, in particularautomotive paints and dispersion colors.

[0004] The function of polymers in pigment dispersions is manifold. Theymay act as solubilisers in the given dispersing agent, e.g. water ororganic solvents. Suitable polymers are also needed as stabilizers toprevent precipitation or flocculation. Polymers may also improve thegloss of the pigment dispersion or enhance its rheology. Depending onthe type and polarity of the dispersing agent, e.g. water, organicsolvents or mixtures thereof, polymers of variable structure are chosen.In view of ecological requirements, the use of aqueous pigmentdispersions is particularly preferred.

[0005] Group transfer polymerization (GTP) is a method for producingacrylic A-B block copolymers of defined structure. With a hydrophilic,“B” block (neutralized acid or amine containing polymers), thesepolymers are useful for preparing water based pigment dispersions. Thehydrophobic “A” blocks (homo- or copolymers of methacrylate monomers)are surface active and associate with either pigment or emulsion polymersurfaces, cf. H. J. Spinelli, Progress in Organic Coatings 27 (1996),255-260.

[0006] The GTP method still has several drawbacks. Thehydrophilic/hydrophobic “balance” is obtained by copolymerizing alimited group of specific acrylate and methacrylate monomers. Moreover,the polymerization initiators used in this method, such as the silylketene acetals disclosed in U.S. Pat. No. 4,656,226, e.g.1-trimethylsilyloxy-1-isobutoxy-2-methylpropene, are highly reactive andthis necessitates the use of carefully dried and purified reactants,which limits the use of this method in industrial applications.

[0007] Therefore, it is desirable to employ an improved method ofpolymerization for preparing polymers of defined structure for use inpigment dispersions.

[0008] U.S. Pat. No. 4,581,429 discloses a free radical polymerizationprocess by controlled or “living” growth of polymer chains whichproduces defined oligomeric homopolymers and copolymers, including blockand graft copolymers. A process embodiment is the use of initiators ofthe partial formula R′R″N—O—X. In the polymerization process the freeradical species R′R″N−O∘ and ∘X are generated. ∘X is a free radicalgroup, e.g. a tert.-butyl or cyanoisopropyl radical, capable ofpolymerizing monomer units containing ethylene groups. The monomer unitsA are substituted by the initiator fragments R′R″N—O∘and ∘X andpolymerize to structures of the type: R′R″N—O-A-X (A: polymer block).Specific R′R″N—O—X initiators mentioned are derived from cyclicstructures, such as 2,2,6,6-tetramethylpiperidine, or open chainmolecules, such as di-tert.-butylamine.

[0009] WO 96/30421 discloses a controlled or “living” polymerizationprocess of ethylenically unsaturated polymers such as styrene or(meth)acrylates by employing the ATRP method. According to this methodinitiators are employed which generate a radical atom such as ∘Cl, inthe presence of a redox system of transition metals of differentoxidation states, e.g. Cu(I) and Cu(II), providing “living” orcontrolled radical polymerization.

[0010] It has surprisingly been found that polymers obtained bycontrolled or “living” polymerization process of ethylenicallyunsaturated polymers, such as styrene or (meth)acrylates, by employingthe ATRP method or related methods are particularly useful for preparingpigment compositions or pigment dispersions prepared from thesecompositions.

[0011] The present invention relates to a composition comprising

[0012] a) 0.1-99.9% by weight of a block copolymer of the formula:

[0013] wherein:

[0014] In represents a polymerization initiator fragment of apolymerization initiator capable of initiating atomic transfer radicalpolymerization (ATRP) of ethylenically unsaturated monomers in thepresence of a catalyst capable of activating controlled radicalpolymerization;

[0015] p represents a numeral greater than zero and defines the numberof initiator fragments;

[0016] A and B represent polymer blocks which differ in polarity andconsist of repeating units of ethylenically unsaturated monomers;

[0017] x and y represent numerals greater than zero and define thenumber of monomer repeating units in polymer blocks A and B;

[0018] X represents a polymer chain terminal group; and

[0019] q represents a numeral greater than zero; and

[0020] b) 0.1-99.9% by weight of dispersible inorganic or organicpigment particles, provided that thermosetting compositions areexcluded.

[0021] The present invention also relates to a pigment dispersioncomprising a dispersed phase consisting of

[0022] a) a block copolymer of the formula I, wherein In, A, B, X, x, y,p and q are as defined above; and

[0023] b) dispersed pigment particles;

[0024] and a liquid carrier selected from the group consisting of water,organic solvents and mixtures thereof.

[0025] The pigment dispersions are useful for variety of uses, e.g. thepreparation of inks or printing inks in printing processes, such asflexographic, screen, packaging, security ink, intaglio or offsetprinting, for pre-press stages and for textile printing, for office,home or graphic applications, for paper goods, for pens, felt tips,fiber tips, card, wood, (wood) stains, metal, inking pads, or inks forimpact printing, (with impact-pressure ink ribbons), or for thepreparation of colorants, for coatings, e.g. paints, for textiledecoration and industrial marking, for roller coatings or powdercoatings or powder coatings or for automotive finishes for high-solids,low-solvent, water containing or metallic coating materials or forwater-containing formulations, water-containing paints, or for thepreparation of pigment plastics for coatings, fibers, platters or moldcarriers, or for non-impact printing material, for digital printing, forthermal wax transfer printing, for inkjet printing or for thermaltransfer printing, or for the preparation of color filters, especiallyfor visible light in the range from 400 to 700 nm, which can be used forthe production of liquid crystal displays (LCDs) or charge combineddevices (CCDs) or for the preparation of cosmetics, toners, or polymericink particles for the preparation of toners for dry copy toners andliquid copy toners, or electrophotographic toners. The toners can beprepared in masterbatches and be used in turn in masterbatches for thepreparation of colored plastics.

[0026] The terms and definitions used in the specification of thepresent invention preferably have the following meanings:

[0027] In the context of the description of the present invention, theterm alkyl comprises methyl, ethyl and the isomers of propyl, butyl,pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl and dodecyl. Anexample of aryl-substituted alkyl is benzyl. Examples of alkoxy aremethoxy, ethoxy and the isomers of propoxy and butoxy. Examples ofalkenyl are vinyl and allyl. An example of alkylene is ethylene,n-propylene, 1,2- or 1,3-propylene.

[0028] Some examples of cycloalkyl are cyclopropyl, cyclobutyl,cyclopentyl, cyclohexyl, methylcyclopentyl, dimethylcyclopentyl andmethylcyclohexyl. Examples of substituted cycloalkyl are methyl-,dimethyl-, trimethyl-, methoxy-, dimethoxy-, trimethoxy-,trifluoromethyl-, bis-trifluoromethyl- andtris-trifluoromethyl-substituted cyclopentyl and cyclohexyl.

[0029] Examples of aryl are phenyl and naphthyl. Examples of aryloxy arephenoxy and naphthyloxy. Examples of substituted aryl are methyl-,dimethyl-, trimethyl-, methoxy-, dimethoxy-, trimethoxy-,trifluoromethyl-, bis-trifluoromethyl- ortris-trifluoromethyl-substituted phenyl. An example of aralkyl isbenzyl. Examples of substituted aralkyl are methyl-, dimethyl-,trimethyl-, methoxy-, dimethoxy-, trimethoxy-, trifluoromethyl-,bis-trifluoromethyl or tris-trifluoromethyl-substituted benzyl.

[0030] Some examples of an aliphatic carboxylic acid are acetic,propionic or butyric acid. An example of a cycloaliphatic carboxylicacid is cyclohexanoic acid. An example of an aromatic carboxylic acid isbenzoic acid. An example of a phosphorus-containing acid ismethylphosphonic acid. An example of an aliphatic dicarboxylic acid ismalonyl, maleoyl or succinyl. An example of an aromatic dicarboxylicacid is phthaloyl.

[0031] The term heterocycloalkyl embraces within the given structure oneor two and heteroaryl one to four heteroatoms, the heteroatoms beingselected from the group consisting of nitrogen, sulfur and oxygen. Someexamples of heterocycloalkyl are tetrahydrofuryl, pyrrolidinyl,piperazinyl and tetrahydrothienyl. Some examples of heteroaryl arefuryl, thienyl, pyrrolyl, pyridyl and pyrimidinyl.

[0032] An example of a monovalent silyl radical is trimethylsilyl.

[0033] Component a)

[0034] In a block copolymer (I) the group In represents thepolymerization initiator fragment of a polymerization initiator:

[0035] wherein In, p and q are as defined above, which is capable ofinitiating atomic transfer radical polymerization of the fragments A andB and subsequently proceeds by a reaction mechanism known under the termATRP or related methods. A suitable polymerization initiator, whichcontains a radically transferable atom or group ∘X, is described in WO96/30421 and WO 98/01480. A preferred radically transferable atom orgroup ∘X is ∘Cl or ∘Br, which is cleaved as a radical from the initiatormolecule and subsequently replaced after polymerization as a leavinggroup with a N→O compound. The index p is 1 if one group ∘X is present(q=1) in the polymerization initiator (II). The polymerization initiatormay also contain more than one groups ∘X. In this case q may be 2 or 3.The polymerization initiator may also be bifunctional. In this case pand q may be two.

[0036] A preferred polymerization initiator (II) is selected from thegroup consisting of C₁-C₈-alkyl halides, C₆-C₁₅-aralkylhalides,C₂-C₈-haloalkyl esters, arene sulfonyl chlorides, haloalkanenitriles,α-halbacrylates and halolactones.

[0037] Specific initiators are selected from the group consisting ofα,α′-dichloro- or α,α′-dibromo-xylene, p-toluenesulfonylchloride (PTS),hexakis-(α-chloro- or α-bromomethyl)benzene, 2-chloro- or2-bromopropionic acid, 2-chloro- or 2-bromoisobutyric acid, 1-phenethylchloride or bromide, methyl or ethyl 2-chloro- or 2-bromopropionate,ethyl-2-bromo- or ethyl-2-chloroisobutyrate, chloro- orbromoacetonitrile, 2-chloro- or 2-bromopropionitrile,α-bromo-benzacetonitrile and α-bromo-γ-butyrolactone(=2-bromo-dihydro-2(3H)-furanone).

[0038] The term polymer comprises oligomers, cooligomers, polymers orcopolymers, such as block, multi-block, star, gradient, random, comb,hyperbranched and dendritic copolymers as well as graft or copolymers.The block copolymer units A and B contain at least two repeating unitsof polymerizable aliphatic monomers containing one or more olefinicdouble bonds.

[0039] The aliphatic monomer units present in A and B differ in polarityand contain one or more olefinic double bonds. The difference inpolarity is obtained by copolymerizing polymer blocks A and B withdifferent amounts of monomers, which contain hydrophilic functionalgroups present in ionic surfactants such as the carboxylate,sulfoxylate, phosphonate, ammonio, alkylated ammonio or hydroxy groups.In a preferred embodiment of the invention the content of monomerscontaining functional groups in each polymer block A or B differs fromthe other polymer block by at least 20% by weight. Particularlypreferred are acrylic A-B block copolymers of defined structure preparedby the ATRP method or related methods. With a hydrophilic “B” block(neutralized acid or amine containing polymers), the presence of thesepolymer blocks is useful for preparing water based pigment dispersions.The hydrophobic “A” blocks (homo- or copolymers of methacrylatemonomers) are surface active and associate with either pigment oremulsion polymer surfaces.

[0040] Both polymer blocks A and B may contain repeating units ofpolymerizable monomers having one olefinic double bond. These monomersare selected from the group consisting of styrenes, acrolein and acrylicor C₁-C₄-alkylacrylic acid-C₁-C₂₄-alkyl esters.

[0041] Suitable styrenes may be substituted at the phenyl group by oneto three additional substituents selected from the group consisting ofhydroxy, C₁-C₄-alkoxy, e.g. methoxy or ethoxy, halogen, e.g. chloro, andC₁-C₄-alkyl, e.g. methyl or methyl.

[0042] Suitable acrylic or C₁-C₄-alkylacrylic acid-C₁-C₂₄-alkyl estersare selected from the group consisting of methyl, ethyl, n-butyl,isobutyl, tert.-butyl, 2-ethylhexyl, isobomyl, isodecyl, lauryl,myristyl, stearyl, and behenyl methacrylates and the correspondingacrylates.

[0043] Examples of monomers containing two or more double bonds arediacrylates of ethylene glycol, propylene glycol, neopentyl glycol,hexamethylene glycol or of bisphenol A,4,4′-bis(2-acryloyloxyethoxy)-diphenylpropane, trimethylolpropanetriacrylate or tetraacrylate.

[0044] In a preferred embodiment of the invention the polymer block B ismore hydrophilic as compared to polymer block A and consists of higheramounts of monomers carrying functional groups. The monomers areselected from the group consisting of acrylic or C₁-C₄-alkylacrylic acidor anhydrides and salts thereof, acrylic or C₁-C₄-alkylacrylicacid-mono- or -di-C₁-C₄-alkylamino-C₂-C₄-alkyl esters and salts thereof,acrylic or C₁-C₄-alkylacrylic acid-hydroxy-C₂-C₄-alkyl esters, acrylicor C₁-C₄-alkylacrylic acid-(C₁-C₄-alkyl)₃silyloxy-C₂-C₄-alkyl esters,acrylic or C₁-C₄-alkylacrylic acid-(C₁-C₄-alkyl)₃silyl-C₂-C₄-alkylesters, acrylic or C₁-C₄-alkylacrylic acid-heterocyclyl-C₂-C₄-alkylesters and salts thereof, C₁-C₂₄-alkoxylated poly-C₂-C₄-alkylene glycolacrylic or C₁-C₄-alkylacrylic acid esters, acrylic orC₁-C₄-alkylacrylamides, acrylic or C₁-C₄-alkylacrylmono- or-di-C₁-C₄-alkylamides, acrylic orC₁-C₄-alkylacryl-di-C₁-C₄-alkylaminoC₂-C₄-alkylamides and salts thereof,acrylic or C₁-C₄-alkylacryl-amino-C₂-C₄alkylamides, acrylonitrile,methacrylonitrile, 4-aminostyrene and salts thereof,di-C₁-C₄-alkylaminostyrene and salts thereof, vinyl substitutedheterocycles, styrene sulfonic acid and salts, vinylbenzoeic acid andsalts, vinylformamide and amidosulfonic acid derivatives.

[0045] The above-mentioned salts are obtained by reaction with organicor inorganic acids or by quatemization.

[0046] Specific examples of the above-mentioned functional monomers areacrylic acid or methacrylic acid, acid anhydrides and salts thereof,e.g. acrylic acid or methacrylic acid-(C₁-C₄-alkyl)ammonium salts,acrylic acid or methacrylic acid-(C₁-C₄-alkyl)₃NH salts, such as theacrylic acid or methacrylic acid tetramethylammonium salt, thetetraethyl-ammonium, trimethyl-2-hydroxyethylammonium or thetriethyl-2-hydroxyethylammonium salt, the acrylic acid or methacrylicacid trimethyl ammonium salt, the triethylammonium,dimethyl-2-hydroxyethylammonium or the dimethyl-2-hydroxyethylammoniumsalt.

[0047] Specific examples of C₁-C₄-alkylacrylic acid-mono- or-di-C₁-C₄-alkylamino-C₂-C₄-alkyl esters are acrylic or methacrylicacid-2-monomethylaminoethylester, acrylic or methacrylicacid-2-dimethylaminoethylester or the 2-monoethylaminoethyl or2-diethylaminoethyl esters or the acrylic or methacrylicacid-2-tert.-butylaminoethylester as well as the corresponding salts ofthese amino substituted (meth)acrylates.

[0048] Specific examples of acrylic or C₁-C₄-alkylacrylicacid-hydroxy-C₂-C₄-alkyl esters are acrylic or methacrylicacid-2-hydroxyethylester (HEA, HEMA) or acrylic or methacrylicacid-2-hydroxypropylester (HPA, HPMA).

[0049] Specific examples of the above-mentioned C₁-C₄-alkylacrylicacid-heterocyclyl-C₂-C₄-alkyl esters are acrylic or methacrylicacid-2-(N-morpholinyl)-ethyl ester. Acrylic or C₁-C₄-alkylacrylicacid-silyloxy-C₂-C₄-alkyl esters are exemplified by acrylic ormethacrylic acid-2-trimethylsilyloxyethylester (TMS-HEA, TMS-HEMA).Acrylic or C₁-C₄-alkylacrylic acid-(C₁-C₄-alkyl)₃silyl-C₂-C₄-alkylesters are exemplified by acrylic or methacrylicacid-2-trimethylsilylethylester or acrylic or methacrylicacid-3-trimethylsilyl-n-propylester. C₁-C₂₄-Alkoxylatedpoly-C₂-C₄-alkylene glycol acrylic or C₁-C₄-alkylacrylic acid esters areexemplified by acrylates and methacrylates of the formula:

[0050] wherein R₁ and R₂ independently of one another represent hydrogenor methyl and R₃ represents C₁-C₂₄-alkyl, such as methyl, ethyl, n- orisopropyl, n-, iso-, or tert.-butyl, n- or neopentyl, lauryl, myristylor stearyl or aryl-C₁-C₂₄-alkyl, such as benzyl or phenyl-n-nonyl,C₁-C₂₄-alkylaryl or C₁-C₂₄-alkylaryl-C₁-C₂₄-alkyl.

[0051] Acrylic or C₁-C₄-alkylacrylic acid-heterocyclyl-C₂-C₄-alkylesters are exemplified by acrylic or methacrylic acid-2-(2-pyridyl,-1-imidazolyl, -2-oxo-1-pyrrolidinyl, -4-methylpiperidin-1-yl, or-2-oxo-imidazolidin-1-yl)-ethyl ester.

[0052] The above-mentioned acrylic or C₁-C₄-alkylacrylamides, acrylic orC₁-C₄-alkylacrylmono- or -di-C₁-C₄-alkylamides, acrylic orC₁-C₄-alkylacryl-di-C₁-C₄-alkylamino-C₂-C₄-alkylamides and acrylic orC₁-C₄-alkylacryl-amino-C₂-C₄alkylamides are exemplified by acrylamide,methacrylamide, N,N-dimethylacrylamide, N,N-dimethyl(meth)acrylamide,2-(N,N-dimethyl-aminoethyl)-acrylamide,2-(N,N-dimethylaminoethyl)-methacrylamide,2-(N,N-dimethyl-aminopropyl)-methacrylamide, 2-aminoethylacrylamide and2-aminoethylmethacrylamide.

[0053] Vinyl substituted heterocycles are exemplified byvinylpyrrolidone, vinylimidazole, vinylcarbazole and vinylpyridine andamidosulfonic acid derivatives by 2-acrylamido-2-methylpropanesulfonicacid.

[0054] Di-C₁-C₄-alkylaminostyrene are exemplified by4-N,N-dimethylaminostyrene.

[0055] The above-mentioned monomers containing functional groups may bederivatized to render them more hydrophilic as described in U.S. Pat.No. 4,656,226 and EP-A-311 157.

[0056] It is to be understood, that the above described functionalmonomers, especially basic monomers, can also be used in form of theircorresponding salts. For example acrylates, methacrylates or styrenescontaining amino groups can be used as salts with organic or inorganicacids or by way of quatemization with known alkylation agents likebenzyl chloride. The salt formation can also be done as a subsequentreaction on the preformed block copolymer with appropriate reagents. Inan other embodiment, the salt formation is done in situ in formulations,for example by reacting a block copolymer with basic or acidic groupswith appropriate neutralization agents during the preparation of apigment concentrate.

[0057] In a preferred embodiment of the invention the polymer blocks Aor B or both are reaction products with reactive polar monomers selectedfrom the group consisting of glycidyl acrylic or C₁-C₄-alkylacrylic acidesters, 2-isocyanatoethyl acrylic or C₁-C₄-alkylacrylic acid esters andC₃-C₈-alkyl- or C₃-C₈-alkenyl-dicarboxylic acid anhydrides.

[0058] x represents a numeral greater than one and defines the number ofmonomer repeating units in A. The lowest number is two. A preferredrange of x is from 2 to 1000.

[0059] y represents zero or a numeral greater than zero and defines thenumber of monomer repeating units in B. A preferred range of y is from 0to 1000.

[0060] In a block copolymer (I) the preferred molecular weight range ofblocks A and B is from about 1 000 to 100 000 and particularly fromabout 1 000 to 50 000. A highly preferred range is from about 2 000 to15 000.

[0061] In a block copolymer (I) the group X represents a polymer chainterminal group. This terminal group is determined by the polymerizationinitiators used in the ATRP method, especially halogen, especiallychlorine or bromine. Halogen may be undesirable as a chain terminalgroup and can be replaced in a subsequent step by other chain terminalgroups derived from TEMPO (=2,2,6,6-TetraMethylPiperidyl-1-Oxide) andderivatives thereof as represented by the partial formula:

[0062] wherein

[0063] one of R₁ and R₂ represents C₁-C₇-alkyl and the other representsC₁-C₄-alkyl or C₁-C₄-alkyl substituted by C₁-C₄-alkoxycarbonyl orC₁-C₄-alkoxy; or

[0064] R₁ and R₂ together with the adjacent carbon atom both representC₃-C₇-cycloalkyl;

[0065] R₃ and R₄ are as defined as R₁ and R₂;

[0066] R_(a) represents C₁-C₄-alkyl, cyano, C₁-C₄-alkoxycarbonyl,C₁-C₄-alkanoyloxy, C₁-C₄-alkanoyl-oxy-C₁-C₄-alkyl, carbamoyl, mono- ordi- C₁-C₄-alkylcarbamoyl, mono- or di-2-hydroxy-ethylcarbamoyl, amidino,2-imidazolyl, 1-hydroxy-2-hydroxymethyl-2-propylcarbamoyl, or1,1-dihydroxymethyl-2-hydroxycarbamoyl; and

[0067] R_(b) is as defined as R_(a); or

[0068] R_(a) and R_(b) together represent a divalent group and form a5-, 6-, 7- or 8-membered aliphatic or aromatic heterocyclic group, whichmay contain 1-3 additional heteroatoms selected from the groupconsisting of nitrogen, oxygen and sulfur.

[0069] A preferred embodiment relates to a group of the formula:

[0070] which is substituted in 4-position by one or two substituents. Inthe partial formula A₁

[0071] R₁, R₂, R₃ and R₄ represent C₁-C₄-alkyl;

[0072] R₅, R₆, R₇ and R₈ represent hydrogen; and

[0073] one of R₉ and R₁₀ independently of the other represents hydrogenor substituents or R₉ and R₁₀ both represent substituents.

[0074] Representative examples of a group of the formula A₁ are thegroups:

[0075] wherein

[0076] m represents 1;

[0077] R_(a) represents hydrogen, C₁-C₁₈-alkyl which is uninterrupted orinterrupted by one or more oxygen atoms, 2-cyanoethyl, benzoyl,glycidyl, or represents a monovalent radical of an aliphatic carboxylicacid having 2 to 12 carbon atoms, of a cycloaliphatic carboxylic acidhaving 7 to 15 carbon atoms, of an a,b-unsaturated carboxylic acidhaving 3 to 5 carbon atoms or of an aromatic carboxylic acid having 7 to15 carbon atoms;

[0078] m represents 2;

[0079] R_(a) represents a divalent radical of an aliphatic dicarboxylicacid having 2 to 36 carbon atoms;

[0080] n represents 1;

[0081] R_(b) represents C₁-C₁₂-alkyl, C₅-C₇-cycloalkyl, C₇-C₈-aralkyl,C₂-C₁₈-alkanoyl, C₃-C₅-alkenoyl or benzoyl; and

[0082] R_(c) represents C₁-C₁₈-alkyl, C₅-C₇-cycloalkyl, C₂-C₈-alkenylunsubstituted or substituted by a cyano, carbonyl or carbamide group,glycidyl, or represents a group of the formula —CH₂CH(OH)-Z, —CO-Z or—CONH-Z, wherein Z is hydrogen, methyl or phenyl.

[0083] Another particularly preferred embodiment relates to the groupA₁, wherein one of R₉ and R₁₀ represents hydrogen and the other oneC₁-C₄-alkanoylamino.

[0084] Component b)

[0085] Suitable dispersible organic pigments are selected from the groupconsisting of are selected from the azo pigment group consisting of azo,disazo, napthol, benzimidazolone, azocondensation, metal complex,isoindolinone, and isoindoline pigments, the chinophthalon pigment,dioxazine pigment and the polycyclic pigment group consisting of indigo,thioindigo, quinacridones, phthalocyanines, perylenes, perionones,anthraquinones, such as aminoanthraquinones or hydroxyanthraquinones,anthrapyrimidines, indanthrones, flavanthrones, pyranthrones,anthantrones, isoviolanthrones, diketopyrrolopyrrole, and carbazoles,e.g. carbazole violet, pigments, pearlescent flakes and the like.Further examples of organic pigments can be found in the monograph: W.Herbst, K. Hunger “Industrielle organische Pigmente” 2^(nd) Edition,1995, VCH Verlagsgesellschaft, ISBN: 3-527-28744-2.

[0086] Suitable dispersible inorganic pigments are selected from thegroup consisting of metallic flakes, such aluminum, aluminum oxide,calcium carbonate, silicon oxide and silicates, iron(III)oxide,chromium(III)oxide, titanium(IV)oxide, zirconium(IV)oxide, zinc oxide,zinc sulfide, zinc phosphate, mixed metal oxide phosphates, molybdenumsulfide, cadmiumsulfide, carbon black or graphite, vanadates, such asbismuth vanadate, chromates, such as lead(IV)chromate, and molybdates,such as lead(IV)molybdate, and mixtures, crystal forms or modificationsthereof, such as rutil, anatas, mica, talcum or kaoline.

[0087] The composition may contain in addition to componenta)—polymers—and component b)—pigments—conventional binder materials forpreparing coating compositions, e.g. paints, fillers, and otherconventional additives selected from the group consisting ofsurfactants, stabilizers, anti-foaming agents, dyes, plasticizers,thixotropic agents, drying catalysts, anti-skinning agents and levelingagents. The composition may also contain conventional additives, such asantioxidants, light stabilizers, e.g. UV stabilizers or absorbers, forexample those of the hydroxyphenylbenzotriazole,hydroxyphenyl-benzophenone, oxalamide or hydroxyphenyl-s-triazine type,flow control agents, rheology control agents such as fumed silica,microgels, screeners, quenchers or absorbers. These additives can beadded individually or in mixtures, with or without so-called stericallyhindered amines (HALS).

[0088] The composition may contain the above-mentioned polymer componenta) in an amount of 0.1 to 99.9% by weight, preferably 0.1 to 50.0% byweight and particularly preferably 1.0 to 30.0% by weight.

[0089] A particularly preferred embodiment of the invention relates to acomposition comprising

[0090] a) 0.1-99.9% by weight of a block copolymer (I), wherein In, X, pand q are as defined above;

[0091] A represents a polymer block consisting of repeating units ofacrylic or methacrylic acid-C₁-C₂₄-alkyl esters;

[0092] B represents a polymer block consisting of repeating units ofacrylic or methacrylic acid-C₁-C₂₄-alkyl esters which are copolymerizedwith at least 50% by weight of monomers carrying functional groups andwherein the monomers are selected from the group consisting of acrylicor methacrylic acid and salts thereof, acrylic or methacrylic acid-mono-or -di-C₁-C₄-alkylamino-C₂-C₄-alkyl esters and salts thereof, acrylic ormethacrylic acid-hydroxy-C₂-C₄-alkyl esters, acrylic or methacrylamide,acrylic or methacrylic-mono- or -di-C₁-C₄-alkylamides, acrylic ormethacryl-amino-C₂-C₄alkylamides, and vinyl substituted heterocyclesselected from the group consisting of vinylpyrrolidone, vinylimidazoleand vinylcarbazole;

[0093] x and y represent numerals greater than zero and define thenumber of monomer repeating units in A and B; and

[0094] X represents a polymer chain terminal group; and

[0095] b) 0.1-99.9% by weight of dispersible pigment particles.

[0096] Another embodiment of the invention relates to a process forpreparing the above-mentioned composition containing components a) andb) and optionally binder materials, fillers or other conventionaladditives, which comprises copolymerizing by atom transfer radicalpolymerization (ATRP) fragments A and B in the presence of thepolymerization initiator:

[0097] wherein In, p and q are as defined above, and X representsHalogen and a catalytically effective amount of a catalyst capable ofactivating controlled atomic transfer radical polymerization (ATRP),replacing halogen X with a different polymer chain terminal group X′ andadding dispersible pigment particles and optionally binder materials,fillers or other conventional additives.

[0098] The polymerization process may be carried out in the presence ofwater or an organic solvent or mixtures thereof. Additional cosolventsor surfactants, such as glycols or ammonium salts of fatty acids, may beadded to the reaction mixture. The amount of solvent should be kept aslow as possible. The reaction mixture may contain the above-mentionedmonomers or oligomers in an amount of 1.0 to 99.9% by weight, preferably5.0 to 99.9% by weight, and especially preferably 50.0 to 99.9% byweight, based on the monomers present in the polymerizate.

[0099] If organic solvents are used, suitable solvents or mixtures ofsolvents are typically pure alkanes (hexane, heptane, octane,isooctane), hydrocarbons (benzene, toluene, xylene), halogenatedhydrocarbons (chlorobenzene), alkanols (methanol, ethanol, ethyleneglycol, ethylene glycol monomethyl ether), esters (ethyl acetate,propyl, butyl or hexyl acetate) and ethers (diethyl ether, dibutylether, ethylene glycol dimethyl ether,.tetrahydrofurane), or mixturesthereof.

[0100] If water is used as a solvent the reaction mixture can besupplemented with a water-miscible or hydrophilic cosolvent. Thereaction mixture will then remain in a homogeneous single phasethroughout the monomer conversion. Any water-soluble or water-misciblecosolvent may be used, as long as the aqueous solvent medium iseffective in providing a solvent system which prevents precipitation orphase separation of the reactants or polymer products until fullcompletion of the polymerization. Exemplary cosolvents useful in theprocess may be selected from the group consisting of aliphatic alcohols,glycols, ethers, glycol ethers, pyrrolidines, N-alkylpyrrolidinones,N-alkylpyrrolidones, polyethylene glycols, polypropylene glycols,amides, carboxylic acids and salts thereof, esters, organosulfides,sulfoxides, sulfones, alcohol derivatives, hydroxyether derivatives suchas butyl carbitol or cellosolve, amino alcohols, ketones, and the like,as well as derivatives and mixtures thereof. Specific examples includemethanol, ethanol, propanol, dioxane, ethylene glycol, propylene glycol,diethylene glycol, glycerol, dipropylene glycol, tetrahydrofuran, andother water-soluble or water-miscible materials, and mixtures thereof.When mixtures of water and water-soluble or water-miscible organicsolvents are selected for the process, the water to cosolvent weightratio is typically in the range of about 100:0 to about 10:90.

[0101] When monomer mixtures or monomer/oligomer mixtures are used, thecalculation of mol % is based on an average molecular weight of themixture.

[0102] Hydrophilic monomers, polymers and copolymers of the presentinvention can be separated from one another or from the polymerizationreaction mixture by, for example, distillation, precipitation,extraction, changing the pH of the reaction media or by other well knownconventional separation techniques.

[0103] The polymerization temperature may range from about 50° C. toabout 180° C., preferably from about 80° C. to about 150° C. Attemperatures above about 180° C., the controlled conversion of themonomers into polymers may decrease, and undesirable by-products likethermally initiated polymers are formed or decomposition of thecomponents may occur.

[0104] A suitable catalyst capable of activating controlled radicalpolymerization is a transition metal complex catalyst salt is present asan oxidizable complex ion in the lower oxidation state of a redoxsystem. Preferred examples of such redox systems are selected from thegroup consisting of Group V(B), VI(B), VI (B), VII, IB and IIB elements,such as Cu⁺/Cu²⁺, Cu⁰/Cu⁺, Fe⁰/Fe²⁺, Fe²⁺/Fe³⁺, Cr^(2+/)Cr³⁺, Co⁺/Co²⁺,Co²⁺/Co³⁺, Ni⁰/Ni⁺, Ni⁺/Ni²⁺, Ni²⁺/Ni³⁺, Mn⁰/Mn²⁺, Mn²⁺/Mn³⁺, Mn³⁺/Mn⁴⁺or Zn⁺/Zn²⁺.

[0105] The ionic charges are counterbalanced by anionic ligands commonlyknown in complex chemistry of transition metals, such hydride ions (H⁻)or anions derived from inorganic or organic acids, examples beinghalides, e.g. F⁻, Cl⁻, Br⁻or I⁻, halogen complexes with transitionmetals, such as Cu^(I)Br₂ ⁻, halogen complexes of the type BF₄ ⁻, PF₆ ⁻,SbF₆ ⁻ or AsF₆ ⁻, anions of oxygen acids, alcoholates or acetylides oranions of cyclopentadiene.

[0106] Anions of oxygen acids are, for example, sulfate, phosphate,perchlorate, perbromate, periodate, antimonate, arsenate, nitrate,carbonate, the anion of a C₁-C₈carboxylic acid, such as formate,acetate, propionate, butyrate, benzoate, phenylacetate, mono-, di- ortrichloro- or -fluoroacetate, sulfonates, for example methylsulfonate,ethylsulfonate, propylsulfonate, butylsulfonate,trifluoromethylsulfonate (triflate), unsubstituted or C₁-C₄alkyl-,C₁-C₄alkoxy- or halo-, especially fluoro-, chloro- or bromo-substitutedphenylsulfonate or benzylsulfonate, for example tosylate, mesylate,brosylate, p-methoxy- or p-ethoxyphenylsulfonate,pentafluorophenylsulfonate or 2,4,6-triisopropylsulfonate, phosphonates,for example methylphosphonate, ethylphosphonate, propylphosphonate,butylphosphonate, phenylphosphonate, p-methylphenylphosphonate orbenzylphosphonate, carboxylates derived from a C₁-C₈carboxylic acid, forexample formate, acetate, propionate, butyrate, benzoate, phenylacetate,mono-, di- or trichloro- or -fluoroacetate, and also C₁-C₁₂-alcoholates,such as straight chain or branched C₁-C₁₂-alcoholates, e.g. methanolateor ethanolate.

[0107] Anionic ligands and neutral may also be present up to thepreferred coordination number of the complex cation, especially four,five or six. Additional negative charges are counter-balanced bycations, especially monovalent cations such as Na⁺, K⁺, NH₄ ⁺ or(C₁-C₄alkyl)₄N⁺.

[0108] Suitable neutral ligands are inorganic or organic neutral ligandscommonly known in complex chemistry of transition metals. Theycoordinate to the metal ion through a σ-, π-, μ-, η-type bonding or anycombinations thereof up to the preferred coordination number of thecomplex cation. Suitable inorganic ligands are selected from the groupconsisting of aquo (H₂O), amino, nitrogen, carbon monoxide and nitrosyl.Suitable organic ligands are selected from the group consisting ofphosphines, e.g. (C₆H₅)₃P, (i-C₃H₇)₃P, (C₅H₉)₃P or (C₆H₁₁)₃P, di-, tri-,tetra- and hydroxyamines, such as ethylenediamine,ethylenediaminotetraacetate (EDTA),N,N-Dimethyl-N′,N′-bis(2-dimethylaminoethyl)-ethylenediamine (Me₆TREN),catechol, N,N′-dimethyl-1,2-benzenediamine, 2-(methylamino)phenol,3-(methylamino)-2-butanol orN,N′-bis(1,1-dimethylethyl)-1,2-ethanediamine,N,N,N′,N″,N″-pentamethyldiethyl-triamine (PMDETA), C₁-C₈-glycols orglycerides, e.g. ethylene or propylene glycol or derivatives thereof,e.g. di-, tri- or tetraglyme, and monodentate or bidentate heterocyclice⁻ donor ligands.

[0109] Heterocyclic e⁻ donor ligands are derived, for example, fromunsubstituted or substituted heteroarenes from the group consisting offuran, thiophene, pyrrole, pyridine, bis-pyridine, picolylimine,γ-pyran, γ-thiopyran, phenanthroline, pyrimidine, bis-pyrimidine,pyrazine, indole, coumarone, thionaphthene, carbazole, dibenzofuran,dibenzothiophene, pyrazole, imidazole, benzimidazole, oxazole, thiazole,bis-thiazole, isoxazole, isothiazole, quinoline, bis-quinoline,isoquinoline, bis-isoquinoline, acridine, chromene, phenazine,phenoxazine, phenothiazine, triazine, thianthrene, purine, bis-imidazoleand bis-oxazole.

[0110] The oxidizable transition metal complex catalyst can be formed ina separate preliminary reaction step from its ligands or is preferablyformed in-situ from its transition metal salt, e.g. Cu(I)Cl, which isthen converted to the complex compound by addition of compoundscorresponding to the ligands present in the complex catalyst, e.g. byaddition of ethylenediamine, EDTA, Me₆TREN or PMDETA.

[0111] After completing the polymerizing step process, the polymersobtained may be isolated or the N→O compound of the formula:

[0112] which corresponds to the group A₀ and wherein R₁-R₄ and R_(a) andR_(b) are as defined above, is added in-situ. The isolating step of thepresent process may be carried out by known procedures, e.g. bydistilling and filtering off unreacted monomer. After completing thesubstitution of the polymerisate with the N→O compound (III), thecatalyst salt is filtered off, followed by evaporation of the solvent orby precipitation of the N→O polymer (I) in a suitable liquid phase,filtering the precipitated polymer and washing and drying.

[0113] The elimination of the leaving group —X, e.g. halogen, and thesubstitution of the polymerisate with the N→O compound (III) isadvantageously performed in such a way that the polymerisate isdissolved in a solvent and the N→O compound (III) is added. The reactiontakes place within a temperature range from room temperature to theboiling temperature of the reaction mixture, preferably from roomtemperature to 100° C. The transition metal in the oxidizable transitionmetal complex catalyst salt is converted from its lower oxidation statein the above-mentioned redox systems to its higher oxidation state. In apreferred embodiment of the process a Cu(I) complex catalyst salt isconverted to the corresponding Cu(II) oxidation state.

[0114] Because the present polymerization and derivatization with theN→O compound (III) by ATRP is a “living” polymerization, it can bestarted and terminated practically at will. The block copolymers (I) asobtained by the process have a low polydispersity. Preferably thepolydispersity is from 1.01 to 2.2, more preferably from 1.01 to 1.9,and most preferably from 1.01 to 1.5.

[0115] The various advantages of the process of this type allowingflexible polymerization reactions are described by K. Matyjaszewski inACS Symp. Ser. Vol. 685 (1998), pg. 2-30.

[0116] The polymers or copolymers can be further processed and used inmost cases without any further purification step. This is an importantadvantage when industrial scale-up is intended. In specific cases it canbe advantageous to modify the resultant block copolymer by additionalreaction step(s) for example by (complete or partial) neutralization ofincorporated aminofunctional monomers with organic or inorganic acids orby quatemization the same with strong alkylation agents.

[0117] The pigments are added to the polymer dispersant by usingconventional techniques, such as high speed mixing, ball milling, sandgrinding, attritor grinding or two or three roll milling. The resultingpigment dispersion may have a pigment to dispersant binder weight ratioof about 0.1:100 to 1500:1 00.

[0118] The invention also relates to the process for preparing thepigment dispersion, which comprises dispersing in a liquid carrierpigment particles in the presence of a block copolymer of the formula I,wherein I, A, B, X, x, y, p and q are as defined above.

[0119] The organic solvents present in the dispersion are mentionedabove, cf. process, and preferably are polar, water-miscible solventssuch as C₁-C₄alkohols, e.g. methanol, ethanol, or isopropanol, polyols,e.g. glycerol, or ethylene, diethylene, triethylene, triethylene orpropylene glycol.

[0120] In a preferred embodiment of this process, fine pigmentdispersions are prepared by mixing the pigments with a solution of thepolymers, concentrating the resulting mixture by distilling off thesolvents, preferably to dryness, and subjecting the resultingconcentrate to thermal treatment to prepare a mixture comprisingpigments and polymers which may then be subsequently dispersed inaqueous and/or organic solvents.

[0121] The above-mentioned methods for preparing the composition, suchas high speed mixing, ball milling, sand grinding, attritor grinding ortwo or three roll milling may in the alternative be employed whenpreparing the dispersion.

[0122] Likewise of particular interest is a specific embodiment of theabove-mentioned process for preparing the composition, wherein coatingcompositions, for example paints, are prepared. The invention thereforealso relates to compositions, wherein film-forming binders c) forcoatings are added.

[0123] The novel coating composition preferably comprises 0.01-10 partsby weight of the combined components a) and b) in the composition, inparticular 0.05-10 parts, especially 0.1-5 parts, per 100 parts byweight of solid binder c).

[0124] The binder c) can in principle be any binder which is customaryin industry, for example those described in Ullmann's Encyclopedia ofIndustrial Chemistry, 5th Edition, Vol. A18, pp. 368-426, VCH, Weinheim1991, Germany In general, the film-forming binder is based on athermoplastic or thermosetting resin, predominantly on a thermosettingresin. Examples thereof are alkyd, acrylic, polyester, phenolic,melamine, epoxy and polyurethane resins and mixtures thereof. Alsoresins curable by radiation or air drying resins can be used.

[0125] Component c) can be any cold-curable or hot-curable binder; theaddition of a curing catalyst may be advantageous. Suitable catalystswhich accelerate curing of the binder are described, for example, inUllmann's, Vol. A18, p.469.

[0126] Preference is given to coating compositions in which component c)is a binder comprising a functional acrylate resin and a crosslinkingagent. Examples of coating compositions containing specific binders are:

[0127] 1) paints based on cold- or hot-crosslinkable alkyd, acrylate,polyester, epoxy or melamine resins or mixtures of such resins, ifdesired with addition of a curing catalyst;

[0128] 2) two-component polyurethane paints based on hydroxyl-containingacrylate, polyester or polyether resins and aliphatic or aromaticisocyanates, isocyanurates or polyisocyanates;

[0129] 3) one-component polyurethane paints based on blockedisocyanates, isocyanurates or polyisocyanates which are deblocked duringbaking, if desired with addition of a melamine resin;

[0130] 4) one-component polyurethane paints based on atrisalkoxycarbonyltiazine crosslinker and a hydroxyl group containingresin such as acrylate, polyester or polyether resins;

[0131] 5) one-component polyurethane paints based on aliphatic oraromatic urethaneacrylates or polyurethaneacrylates having free aminogroups within the urethane structure and melamine resins or polyetherresins, if necessary with curing catalyst;

[0132] 6) two-component paints based on (poly)ketimines and aliphatic oraromatic isocyanates, isocyanurates or polyisocyanates;

[0133] 7) two-component paints based on (poly)ketimines and anunsaturated acrylate resin or a polyacetoacetate resin or amethacrylamidoglycolate methyl ester;

[0134] 8) two-component paints based on carboxyl- or amino-containingpolyacrylates and polyepoxides;

[0135] 9) two-component paints based on acrylate resins containinganhydride groups and on a polyhydroxy or polyamino component;

[0136] 10) two-component paints based on acrylate-containing anhydridesand polyepoxides;

[0137] 11) two-component paints based on (poly)oxazolines and acrylateresins containing anhydride groups, or unsaturated acrylate resins, oraliphatic or aromatic isocyanates, isocyanurates or polyisocyanates;

[0138] 12) two-component paints based on unsaturated polyacrylates andpolymalonates;

[0139] 13) thermoplastic polyacrylate paints based on thermoplasticacrylate resins or externally crosslinking acrylate resins incombination with etherified melamine resins;

[0140] 14) paint systems based on siloxane-modified or fluorine-modifiedacrylate resins.

[0141] In addition to the components mentioned above, the coatingcomposition according to the invention preferably comprises a lightstabilizer of the sterically hindered amine type, the2-(2-hydroxyphenyl)-1,3,5-triazine and/or the2-hydroxyphenyl-2H-benzotriazole type. Further examples for lightstabilizers of the 2-(2-hydroxyphenyl)-1,3,5-triazine typeadvantageously to be added can be found e.g. in the published patentliterature, e.g. U.S. Pat. No. 4,619,956, EP-A-434608, U.S. Pat. No.5,198,498, U.S. Pat. No. 5,322,868, U.S. Pat. No. 5,369,140, U.S. Pat.No. 5,298,067, WO-94/18278, EP-A-704437, GB-A-2297091, WO-96/28431. Ofspecial technical interest is the addition of the2-(2-hydroxyphenyl)-1,3,5-triazines and/or2-hydroxyphenyl-2H-benzotriazoles, especially the2-(2-hydroxyphenyl)-1,3,5-triazines.

[0142] Apart from the components mentioned above, the coatingcomposition can also comprise further components, examples beingsolvents, pigments, dyes, plasticizers, stabilizers, thixotropic agents,drying catalysts and/or leveling agents. Examples of possible componentsare those described in Ullmann's, Vol. A 18, pp. 429-471.

[0143] Possible drying catalysts or curing catalysts are, for example,organometallic compounds, amines, amino-containing resins and/orphosphines. Examples of organometallic compounds are metal carboxylates,especially those of the metals Pb, Mn, Co, Zn, Zr or Cu, or metalchelates, especially those of the metals Al, Ti or Zr, or organometalliccompounds such as organotin compounds.

[0144] Examples of metal carboxylates are the stearates of Pb, Mn or Zn,the octanoates of Co, Zn or Cu, the naphthenoates of Mn and Co or thecorresponding linoleates, resinates or tallates.

[0145] Examples of metal chelates are the aluminum, titanium orzirconium chelates of acetylacetone, ethyl acetylacetate,salicylaldehyde, salicylaldoxime, o-hydroxyacetophenone or ethyltrifluoroacetylacetate, and the alkoxides of these metals.

[0146] Examples of organotin compounds are dibutyltin oxide, dibutyltindilaurate or dibutyltin dioctoate.

[0147] Examples of amines are, in particular, tertiary amines, forexample tributylamine, triethanolamine, N-methyidiethanolamine,N-dimethylethanolamine, N-ethylmorpholine, N-methylmorpholine ordiazabicyclooctane (triethylenediamine) and salts thereof. Furtherexamples are quaternary ammonium salts, for exampletrimethylbenzylammonium chloride.

[0148] Amino-containing resins are simultaneously binder and curingcatalyst. Examples thereof are amino-containing acrylate copolymers.

[0149] The curing catalyst used can also be a phosphine, for exampletriphenylphosphine.

[0150] The novel coating compositions can also be radiation-curablecoating compositions. In this case, the binder essentially comprisesmonomeric or oligomeric compounds containing ethylenically unsaturatedbonds, which after application are cured by actinic radiation, i.e.converted into a crosslinked, high molecular weight form. Where thesystem is UV-curing, it generally contains a photoinitiator as well.Corresponding systems are described in the above-mentioned publicationUllmann's, Vol. A 18, pages 451-453. In radiation-curable coatingcompositions, the novel stabilizers can also be employed without theaddition of sterically hindered amines.

[0151] The coating compositions according to the invention can beapplied to any desired substrates, for example to metal, wood, plasticor ceramic materials. They are preferably used as topcoat in thefinishing of automobiles. If the topcoat comprises two layers, of whichthe lower layer is pigmented and the upper layer is not pigmented, thenovel coating composition can be used for either the upper or the lowerlayer or for both layers, but preferably for the upper layer.

[0152] The novel coating compositions can be applied to the substratesby the customary methods, for example by brushing, spraying, pouring,dipping or electrophoresis; see also Ullmann's, Vol. A 18, pp. 491-500.

[0153] Depending on the binder system, the coatings can be cured at roomtemperature or by heating. The coatings are preferably cured at 50-150°C., and in the case of powder coatings or coil coatings even at highertemperatures.

[0154] The coatings obtained in accordance with the invention haveexcellent resistance to the damaging effects of light, oxygen and heat;particular mention should be made of the good light stability andweathering resistance of the coatings thus obtained, for example paints.

[0155] The invention therefore also relates to a coating, in particulara paint, which has been stabilized against the damaging effects oflight, oxygen and heat by a content of the compound of the formula (I)according to the invention. The paint is preferably a topcoat forautomobiles. The invention furthermore relates to a process forstabilizing a coating based on organic polymers against damage by light,oxygen and/or heat, which comprises mixing with the coating compositiona mixture comprising a compound of the formula (I), and to the use ofmixtures comprising a compound of the formula (I) in coatingcompositions as stabilizers against damage by light, oxygen and/or heat.

[0156] The coating compositions can comprise an organic solvent orsolvent mixture in which the binder is soluble. The coating compositioncan otherwise be an aqueous solution or dispersion. The vehicle can alsobe a mixture of organic solvent and water. The coating composition maybe a high-solids paint or can be solvent-free (e.g. a powder coatingmaterial). Powder coatings are, for example, those described inUllmann's, A18, pages 438-444. The powder coating material may also havethe form of a powder-slurry (dispersion of the powder preferably inwater).

[0157] Likewise preferred is the use of the coating composition as atopcoat for applications in the automobile industry, especially as apigmented or unpigmented topcoat of the paint finish. Its use forunderlying coats, however, is also possible.

[0158] The above-mentioned coating compositions or disperse systems mayadditionally contain fillers, such as calcium carbonate, silicates,glass fibers, glass beads, talc, kaolin, mica, barium sulfate, metaloxides and hydroxides, carbon black, graphite, wood powders, powders andfibers of other natural products, synthetic fibers, plasticisers,lubricants, emulsifiers, pigments, rheology additives, catalysts, flowauxiliaries, optical brighteners, flame retardants, antistatics, blowingagents.

[0159] The following examples illustrate the invention.

EXAMPLE 1

[0160] Dispersions and Pigmented Coatings Containing Block CopolymersMade by ATRP

[0161] 1. Materials and Methods

[0162] 1.1 Preparation of Polymers

[0163] 1.1.1 Preparation of poly-n-butylacrylate with Terminal Br-Groupsby the ATRP Method without the Addition of Solvent([M]:[I]:[CuBr]:[L]=40:1:0.2:0.2).

[0164] 898.00 g (1000 ml, 7.0 mol) n-butylacrylate (Fluka, purum) and5.02 g (35.0 mmol) CuBr (Fluka, purified by treatment with acetic acid)are added to a 1500 ml round flask equipped with a mechanical stirrer.The air is removed from the flask by stirring, evacuating and rinsingwith nitrogen three times. 6.06 g (7.3 ml, 35 mmol) PMDETA(N,N,N′,N″,N″-pentamethyldiethyltriamine: Fluka/purum) are added throughthe rubber sealing with a syringe. After addition of 29.22 g (19.51 ml,175 mmol) methyl-2-bromo-propionate (initiator MBP) with a syringe andheating up to 80° C. in the oil bath the exothermal polymerizationreaction is started. The temperature rises quickly to 110° C and iscontrolled at a level of 100-105° C. The mixture is polymerized for 75min. The amount produced is determined by ¹H-NMR-analysis in CDCl₃ (98%after 75 min.) After cooling to room temperature 800 ml ethyl acetateand 300 g neutral aluminum oxide (ALOX) are added. After stirring themixture for 1 h at room temperature, filtration, drying in the rotaryevaporator at 80° C. and additional drying with a vacuum pump thepolymer is obtained.

[0165] Elementary analysis: C H Br calc. 64.38 9.26 1.59 found 64.519.27 1.23

[0166] Cu: <10 ppm (X-ray fluorescence); GPC (THF):M_(n): 4970, M_(w):6270, PDI: 1.26; Yield: 845 g (92%).

[0167] 1.1.2 Preparation of a Block Copolymer of n-butylacrylate and2-dimethylaminoethyl Acrylate with Terminal Br-Groups by the ATRP Method([M]:[MI]:[CuBr]:[L]=10:2:1:1; MI:Macroinitiator).

[0168] 100.00 g poly-n-butylacrylate (1.1.1) and 1.437 g (10.0 mmol)CuBr (Fluka, purified by treatment with acetic acid) are added to a 150ml round flask equipped with a mechanical stirrer. The air is removedfrom the flask by stirring, evacuating and rinsing with nitrogen threetimes. The mixture is stirred and 14.37 g (15.35 ml, 100 mmol)2-dimethylaminoethyl acrylate (BASF, technical quality) are addedthrough the rubber sealing with a syringe. The air is removed again fromthe flask by evacuating and rinsing with nitrogen three times. 1.74 g(2.1 ml, 10 mmol) PMDETA (Fluka/purum) are added with a syringe, and themixture is made homogeneous by stirring. After heating up to 80° C. inthe oil bath the slightly exothermal polymerization reaction is startedand the temperature rises up to 87° C. The mixture is polymerized for 80min. The conversion is determined by ¹H-NMR-analysis in CDCl₃ (70%).After cooling to room temperature 400 ml ethyl acetate and 150 g neutralaluminum oxide (ALOX) are added. The polymer is obtained after stirringfor 40 min. at room temperature, filtration and drying in the rotaryevaporator at 80° C. and drying in the vacuum pump.

[0169] Elementary analysis: C H N Br calc. 63.65 9.25 1.23 1.40 found64.37 8.77 0.83 0.59

[0170] Cu: <57 ppm (X-ray fluorescence); GPC (THF): M_(n): 8830, M_(w):7760, PDI: 1.33; Yield: 94.62 9 (83%).

[0171] 1.1.3 Preparation of a Block Copolymer of n-butylacrylate and2-hydroxyethyl Acrylate with Terminal Br-Groups by the ATRP Method([M]:[MI]:[CuBr]:[L]=10:2:1:1).

[0172] 100.00 g poly-n-butylacrylate (1.1.1) and 1.437 g (10.0 mmol)CuBr (Fluka, purified by treatment with acetic acid) are added to a 150ml round flask equipped with a mechanical stirrer. The air is removedfrom the flask by stirring, evacuating and rinsing with nitrogen threetimes. The mixture is stirred and 11.66 g (10.54 ml, 100 mmol)2-dimethylaminoethyl acrylate (HEA, Fluka, purum) are added through therubber sealing with a syringe. The air is removed again from the flaskby evacuating and rinsing with nitrogen three times. 1.74 g (2.1 ml, 10mmol) PMDETA (Fluka/purum) are added with a syringe, and the mixture ismade homogeneous by stirring. After heating up to 80° C. in the oil bathfor one hour and control by 1H-NMR-analysis in CDCl₃, the conversionreached almost 100%. After cooling to room temperature, adding 1000 mlethyl acetate and 200 g neutral aluminum oxide (ALOX), stirring for 40min. at room temperature, filtration, and drying in the rotaryevaporator at 80° C. and the vacuum pump, the polymer is obtained.

[0173] Elementary analysis: C H Br calc. 63.04 9.02 1.44 found 63.749.25 0.61

[0174] Cu: <46 ppm (X-ray fluorescence); GPC (THF): M_(n): 7000, M_(w):12000, PDI: 1.72; Yield: 91.76 g (82%).

[0175] 1.1.4 Preparation of Additional Block Copolymers

[0176] 1.1.4.1.1

[0177] n-Butyl acrylate (n-BA) is polymerized with MBP according to Ex.1.1.1 to obtain linear poly(n-BA) with Br-end groups (M_(n)=5620,M_(w)=6690, PDI=1.19, Br (found): 1.22%).

[0178] 1.1.4.1.2

[0179] 120.0 g poly(n-BA), see Ex. 1.1.1.4.1, and 1.61 g (12.2 mmol)CuBr (Fluka, purified by treatment with acetic acid) are added to a 350ml round flask equipped with a mechanical stirrer. The air is removed bystirring, evacuating and rinsing three times with nitrogen. 38.82 g(41.4 ml, 271 mmol) 2-dimethylaminoethyl acrylate (BASF, technicalquality) are added with a syringe through the rubber septum. The air isremoved again from the mixture by evacuating and rinsing with nitrogen.After making the mixture homogeneous by stirring 2.58 g (3.0 ml, 12.2mmol) Me₆TREN (synthesized by methylating tris-(2-aminoethyl)amine(=TREN) with formaldehyde according to Beilstein E IV, Vol. 4, pg. 1251;El. Anal.: % caic. C: 62.55, H: 13.12, N: 24.32, % found C: 62.22, H:13.29; N: 24.54) is added. The polymerization then is started, and thetemperature rises to 60° C. After one hour of polymerization time themixture is purged with air, and the conversion is determined by ¹H-NMRanalysis in CDCl₃ (90 %). 300 ml ethyl acetate and 60 g neutral aluminumoxide (ALOX) are added. The polymer is obtained after stirring for 1 hat room temperature, filtration and drying at 100° C. under vacuum inthe rotary evaporator. Yield: 145.6 g (94 %).

[0180] Elementary analysis: C H N Br calc. 63.30 9.28 2.44 1.14 found63.51 9.35 2.12 0.44

[0181] GPC (THF): M_(n)=7320, M_(w)=9300, PDI=1.27.

[0182] 1.1.4.1.3

[0183] 80 g Poly(BA-b-DMAEA), cf. Ex. 1.1.4.1.2, is dissolved in 58.32 g(66.2 ml) ethyl acetate in a 350 ml round flask equipped with amechanical stirrer. 7.49 g (59.2 mmol, 50% of the amine content of theblock copolymer) benzyl chloride (Fluka, puriss) are added thereto. Themixture is homogenized with stirring and heated to 85° C. for 2 h. Theeffective quatemization of the tertiary amino group in the copolymer isca. 50%, as proven by ¹H-NMR in CDCl₃ (change of the chemical shift ofca. 50% of the benzylic methylene group protons from 4.6 to 4.9 ppm).After cooling the yellow solution (60 wt % polymer in EtOAc) is used forpreparing the compositions. Yield: 139.6 g (96%), GPC (DMF): M_(n)=7400,M_(w)=9470, PDI=1.28.

[0184] 1.1.4.1.4

[0185] 80 g Poly(BA-b-DMAEA), cf. Ex. 1.1.4.1.2, is dissolved in 62.78 g(71.3 ml) ethyl acetate in a 350 ml round flask equipped with amechanical stirrer. 14.18 g (112 mmol, 95% of the amine content of theblock copolymer) benzyl chloride (Fluka, puriss) are added thereto. Themixture is homogenized with stirring and heated to 85° C. for 2 h. Dueto increasing viscosity the mixture is diluted with additional 125.5 g(142 ml) EtOAc. The quatemization of the tertiary amino group of thecopolymer is ca. 95%, as proven by ¹H-NMR in CDCl₃: change of thechemical shift of ca. 95% of the benzylic methylene group protons from4.8 to 5.1 ppm. After cooling the yellow solution (30 wt % polymer inEtOAc) is used for preparing the compositions. Yield: 290.9 g (93%), GPC(DMF): M_(n)=6160, M_(w)=8930, PDI=1.45.

[0186] 1.1.4.1.5

[0187] 83 g Poly(BA-b-DMAEA), cf. Ex. 1.1.4.1.2, is dissolved in 245.4 g(279 ml) ethyl acetate in a 350 ml round flask equipped with amechanical stirrer. 22.17 g (116 mmol, 95% of the amine content of theblock copolymer) p-toluene sulfonic acid monohydrate (Merck p.a.) areadded thereto. The mixture is homogenized with stirring for 2 h at roomtemperature. The protonation of the tertiary amino group of thecopolymer is ca. 95%, as proven by ¹H-NMR in CDCl₃: change of thechemical shift of ca. 95% of the —N(CH₃)₂ group protons from 2.2 to 3.3ppm. After cooling the yellow solution (30 wt % polymer in EtOAc) isused for preparing the compositions. Yield: 342.7 g, GPC (DMF):M_(n)=6160, M_(w)=8930, PDI=1.45.

[0188] 1.1.4.2.1

[0189] n-Butyl acrylate (n-BA) is polymerized with MBP according to Ex.1.1.1 to obtain linear poly(n-BA) with Br-end groups (M_(n)=13780,M_(w)=15640, PDI=1.13, Br (found): 0.48%.

[0190] 1.1.4.2.2

[0191] The synthesis is performed as described in Ex. 1.1.4.1.2 with120.0 g poly(n-BA), see Ex. 1.1.4.2.1, 0.62 g (4.35 mmol) CuBr, 17.95 g(125 mmol) 2-dimethylamino-ethyl acrylate (DMAEA) and 1.0 g (3.0 ml,4.35 mmol) Me₆TREN. 4 h polymerization time at room temperature isneeded for the conversion (¹H-NMR, CDCl₃:90%). Yield: 139.8 g (98%).

[0192] Elementary analysis: C H N Br calc. 64.31 9.34 1.24 0.54 found64.33 9.52 1.16 0.18

[0193] GPC (THF): M_(n)=15480, M_(w)=18730, PDI=1.21.

[0194] 1.1.4.3

[0195] The synthesis is performed as described in Ex. 1.1.4.1.2 but withCuCl as catalyst, PMDETA as ligand precursor and Br-terminatedpoly(n-BA).

[0196] 120.0 g poly(n-BA), see Ex. 1.1.4.1, 1.90 g (19.2 mmol) CuCl(Fluka, purified by. treatment with acetic acid), 41.95 g (226 mmol)tert-butyl-aminoethyl acrylate (tBAEMA, AGIFLEX FMA, Ciba S.C. (AlliedColloids)), 3.33 g (4.0 ml, 19.2 mmol) PMDETA. 45 min. polymerizationtime at 90° C. Conversion (¹H-NMR, CDCl₃): ca. 100%. Yield: 147.4 g(91%).

[0197] Elementary analysis: C H N Cl calc. 64.94 9.62 2.06 0.49 found64.98 9.67 1.77 0.22

[0198] GPC (DMF): M_(n)=9520, M_(w)=11610, PDI=1.22.

[0199] 1.1.4.4.1

[0200] n-Butyl acrylate (n-BA) is polymerized with MBP according to Ex.1.1.1 to obtain linear poly(n-BA) with Br-end groups; M_(n)=4970,M_(w)=6270, PDI=1.26, Br (found): 1.24%.

[0201] 1.1.4.4.2

[0202] 135.4 g poly(n-BA), see Ex. 1.1.4.41 above, and 3.9 9 (27.2 mmol)CuBr (Fluka, purified by treatment with acetic acid) are added to a 350ml round flask equipped with a mechanical stirrer. The air is removed bystirring, evacuating and rinsing with nitrogen three times. 52.26 g(59.2 ml, 271 mmol) tert-butyl acrylate (tBA, Fluka, puriss) are addedthrough the rubber septum with a syringe. The air is removed again fromthe mixture by evacuating and rinsing with nitrogen. The mixture isheated to 90° C. on an oil bath and made homogeneous by stirring. 4.71 g(5.67 ml, 27.2 mmol) PMDETA is added with a syringe thus initiating aslightly exothermic polymerization reaction. After 2 h of reaction timethe mixture is cooled to room temperature and purged with air. Theconversion is determined by ¹H-NMR-analysis in CDCl₃ and is about 100%.2×150 ml ethyl acetate and 2×100 g neutral aluminum oxide (ALOX) areadded to the reaction mixture which is then stirred each time for 1 h atroom temperature stirred and filtered. The pure dried polymer isobtained after evaporating the solvent in a rotary evaporator at 80° C.for 1 h with a vacuum pump. Yield: 168.9 g (90 %), GPC (THF):M_(n)=8220, M_(w)=11100, PDI=1.34.

[0203] 1.1.4.4.3

[0204] 100.0 g of the polymer (poly(BA-b-tBA)), see Ex. 1.1.1.4.4.2, isdissolved in 100 ml methylene chloride in a 500 ml round bottom flaskequipped with mechanical stirring. 74.34 g (49.89 ml, 3 equivalentsrelative to tBA content of the block copolymer) trifluoroacetic acid(TFA), are added thereto. The mixture is stirred for 22 h at roomtemperature. The solvents (CH₂Cl₂ and TFA) are removed in the rotaryevaporator (1 h, 80° C., p<0.1 mbar). Yield: ca. 100%. The cleavage ofthe tert-butyl group is quantitative as proven by the ¹H-NMR (DMSO-d₆):disappearance of signal at 1.4 ppm and appearance of signal at 12.1 ppm(-COOH). GPC (THF): M_(n)=5670; M_(w)=6920; PDI=1.22; Acid content(titration): 2.20 meq./g.

[0205] 2. Experimental

[0206] The performance of the different block copolymers is evaluated ina “concentrated” polyester millbase and corresponding coatingformulations made therefrom. A polyester millbase formulation is used totest the rheological behavior at relatively high pigment loadings. Themillbase-formulation is used to grind and disperse the pigments. Afterdefined grinding (2 h, Scandex-Mixer) the viscosity of the dispersion ismeasured at different shear rates with a cone plate viscosimeter.Reduction of the viscosities is indicative for dispersant efficiency,especially at low shear rates. The reference formulation contains nodispersant, but the same weight ratio of pigment versus polymer(=binder+dispersant) is maintained in each case. A letdown formulation(=final lacquer) is prepared from the millbase concentrate and appliedto a transparent plastic film substrate or a glass plate and cured athigh temperature. Gloss measurements were done on the cured coatings tocharacterize the dispersion quality of the pigment in the finishedcoating. Improved gloss is indicative for good dispersion of thepigment. In each case the reference formulation contains the same ratioof pigment versus polymer(=polyester+CAB+Melamine-crosslinker+dispersant). The following blockcopolymers were used: Poly- Composition (wt %)¹⁾ mer Initiator Molecularweight²⁾ P(BA-b-DMAEA) = 88-12 1 MBP Mw = 6250, Mn = 7870; PDI = 1.26P(BA-b-HEA) = 90-10 2 MBP Mw = 7630, Mn = 12510 PDI = 1.61 P(BA-b-DMAEA)= 76-24 3 MBP M_(n) = 7320, M_(w) = 9300, PDI = 1.27 P(BA-b-DMAEA) =87-13 4 MBP M_(n) = 15480, M_(w) = 18730, PDI = 1.21 P(BA-b-tBAEMA) =73-27 5 MBP M_(n) = 9520, M_(w) = 11610, PDI = 1.22 P(BA-b-tBAEMA) =73-27 6 MBP M_(n) = 9520, M_(w) = 11610, PDI = 1.22 P(BA-b-DMAEA) =87-13 7 MBP M_(n) = 7400, M_(w) = 9470, (50% quaternized PDI = 1.28 withBzCl) P(BA-b-DMAEA) = 87-13 9 MBP M_(n) = 9590, M_(w) = 11500, (50%neutralized PDI = 1.20 with pTSA) P(BA-b-DMAEA) = 87-13 10 MBP M_(n) =6160, M_(w) = 8930, (95% neutralized PDI = 1.45 with pTSA) P(BA-b-AA) =82-18 11 MBP M_(n) = 5670, M_(w) = 6920, PDI = 1.22 P(BA-b-AA) = 85-1512 MBP M_(n) = 5800, M_(w) = 10340, (neutralized with PDI = 1.30 50% TOA

[0207] 3. Results

[0208] As can be seen from the results with different organic pigmentsin Tables 1, 3 and 5, the millbase formulations containing blockcopolymers show improved rheology as compared to the reference withoutdispersant. In the final lacquer formulations, the block copolymers alsoshow improvements in gloss, cf. Tables 2, 4 and 6. TABLE 1 Performanceevaluation in a polyester mill base concentrate containing the organicpigment Irgazin ® DPP Rubine FTX Millbase Formulation Millbase 2Millbase 3 Components Millbase 1¹⁾ with Polymer 1 with Polymer 2Dynapol ® 43.43 34.29 34.29 H700-08²⁾ (35%) Xylene/Butylacetate 38.4444.38 44.38 (40/60) Butylacetate 2.13 Polymer 1³⁾ (60% in 5.33Butylacetate) Polymer 2⁴⁾ (60% in 5.33 Butylacetate) IRGAZIN DPP 16.0016.00 16.00 Rubine FTX Total 100.00 100.00 100.00 Viscosities (mPas) at:1 rad/s 57010 41530 39480 2 rad/s 31470 23550 23930 4 rad/s 17670 1405015240

[0209] TABLE 2 Performance evaluation in a letdown formulation with theorganic pigment IRGAZIN DPP Rubine FTX Letdown Formulation ComponentsLacquer 1 Lacquer 2 Lacquer 3 Millbase 31.25 31.25 31.25 DYNAPOL H7001¹⁾(60%) 17.27 17.27 17.27 Maprenal ® MF 650²⁾ 2.94 2.94 2.94 CABSolution³⁾ (20%) 26.36 26.36 26.36 Xylene/Butylacetate (40/60) 22.1822.18 22.18 Total 100.00 100.00 100.00 % Gloss (at 60°) 46 60 48

[0210] TABLE 3 Performance evaluation in a polyester mill baseconcentrate containing the organic pigment IRGAZIN DPP Rubine TR:Millbase Formulation Components Millbase 1¹⁾ Millbase 2²⁾ Dynapol ®H700-08³⁾ (35%) 32.57 25.71 Xylene/Butylacetate (40/60) 53.83 58.29Butylacetate 1.60 Polymer⁴⁾ (60% in Butylacetate) 4.00 IRGAZIN DPPRubine TR 12.00 12.00 Total 100.00 100.00 Viscosities (mPas) at: 1 rad/s32700 21070 2 rad/s 17380 11400 4 rad/s 10590 8334

[0211] TABLE 4 Performance evaluation in a letdown formulation with theorganic pigment IRGAZIN DPP Rubine TR Letdown Formulation ComponentsLacquer 1 Lacquer 2 Millbase 41.67 41.67 DYNAPOL H700¹⁾ (60%) 17.2717.27 Maprenal ® MF 650²⁾ 2.94 2.94 CAB Solution³⁾ (20%) 26.36 26.36Xylene/Butylacetate (40/60) 11.77 11.77 Total 100.00 100.00 % Gloss (at60°) 60 74

[0212] TABLE 5 Performance evaluation in a polyester mill baseconcentrate containing the organic pigment Cinquasia ® Scarlet RT-390-D:Millbase Formulation Components Millbase 1¹⁾ Millbase 2²⁾ Dynapol ®H700-08³⁾ (35%) 54.29 42.83 Xylene/Butylacetate (40/60) 23.04 30.50Butylacetate 2.67 Polymer⁴⁾ (60% in Butylacetate) 6.67 IRGAZIN DPPRubine FTX 20.00 20.00 Total 100.00 100.00 Viscosities (mPas) at: 1rad/s 41670 15680 2 rad/s 24960 10150 4 rad/s 15290 6105

[0213] TABLE 6 Performance evaluation in a letdown formulation with theorganic pigment CINQUASIA Scarlet RT-390-D: Letdown FormulationComponents Lacquer 1 Lacquer 2 Millbase 25.00 25.00 DYNAPOL H700¹⁾ (60%)17.27 17.27 Maprenal ® MF 6502) 2.94 2.94 CAB Solution³⁾ (20%) 26.3626.36 Xylene/Butylacetate (40/60) 28.43 28.43 Total 100.00 100.00 %Gloss (at 60°) 60 74

[0214] 3.7 Table 7

[0215] In another set of experiments, the performance of different newblock copolymer dispersants made by ATRP is compared with state of theart commercial dispersants. The same polyester formulation (DYNAPOLH700-08) as “Millbase 2” in Table 3 is used, except that the dispersiontime is extended to 4 h. In all cases the same weight ratio ofdispersant active polymer versus pigment of 20/100 is maintained.Letdown formulations are containing the pigment IRGAZIN DPP Rubine TRprepared according to lacquer 2 in Table 4 to compare the gloss of thecured coating. The results from Table 7 show that the new blockcopolymer dispersants improve the rheology in the millbase and/or thegloss of the cured lacquer. TABLE 7 Viscosity Millbase at Shear Rate:(rad/sec) Let down: Dispersant Composition¹⁾ 1 16 128 Gloss 20°Solsperse ® 24000²⁾ 27700 4930 835 42 Disperbyk ® 161³⁾ 30800 5830 96342 Efka 48⁴⁾ 32900 6900 1150  36  4 P (BA-b-DMAEA) 76 - 24 12800 4820874 27  5 P (BA-b-DMAEA) 87 - 13 14900 5150 908 33  6 P (BA-b-tBAEMA)73 - 27  9280 5760 1040  18  7 P (BA-b-DMAEA) 87 - 13 (50% 37300 4430663 54   quaternized with BzCl)  8 P (BA-b-DMAEA) 87 - 13 (95% 330004500 702 57 quaternized with BzCl)  9 P (BA-b-DMAEA) 87 - 13 (50% 231003540 547 55 neutralized with pTSA) 10 P (BA-b-DMAEA) 87 - 13 (95% 142003680 576 53 neutralized with pTSA) 11 P (BA-b-AA) 82 - 18 35300 3480 56141 12 P (BA-b-AA) 85 - 15 17800 4030 615 43 (neutralized with 50% TOA)

We claim
 1. A composition comprising a) 0.1-99.9% by weight of a blockcopolymer of the formula:

wherein: In represents a polymerization initiator fragment of apolymerization initiator which is selected from the group consisting ofC₁-C₈-alkyl halides, C₆-C₁₅-aralkylhalides, C₂-C₈-haloalkyl esters,arene sulfonyl chlorides, haloalkanenitriles, α-haloacrylates andhalolactones; p represents one or two; A and B represent polymer blockswhich differ in polarity and consist of repeating units of ethylenicallyunsaturated monomers and wherein the difference in polarity is obtainedby copolymerizing polymer blocks A and B with different amounts offunctional monomers; x and y represent numerals greater than zero anddefine the number of monomer repeating units in polymer blocks A and B;X represents a polymer chain terminal group; and q represents a numeralgreater than zero; and b) 0.1-99.9% by weight of dispersible inorganicor organic pigment particles, provided that thermosetting compositionsare excluded:
 2. A composition according to claim 1, wherein Inrepresents the polymerization initiator fragment of a polymerizationinitiator which is selected from the group consisting of C₁-C₈-alkylhalides, C₆-C₁₅-aralkylhalides, C₂-C₈-haloalkyl esters, arene sulfonylchlorides, haloalkanenitriles, α-haloacrylates and halolactones; and prepresents one.
 3. A composition according to claim 1, wherein thedifference in polarity is obtained by copolymerizing polymer blocks Aand B with different amounts of functional monomers.
 4. A compositionaccording to claim 3, wherein the content of functional monomers in eachpolymer block A or B differs from the other polymer block by at least20% by weight.
 5. A composition according to claim 4, wherein thecontent of functional monomers in polymer block B is at least 20% byweight higher as compared to polymer block A.
 6. A composition accordingto claim 1, wherein A and B represent polymer blocks containingrepeating units of polymerizable monomers selected from the groupconsisting of styrenes, acrolein and acrylic or C₁-C₄-alkylacrylicacid-C₁-C₂₄-alkyl esters.
 7. A composition according to claim 1, whereinthe polymer blocks B is more hydrophilic as compared to polymer block Aand consists of higher amounts of monomers carrying functional groupsand wherein the monomers are selected from the group consisting ofacrylic or C₁-C₄-alkylacrylic acid or anhydrides and salts thereof,acrylic or C₁-C₄-alkylacrylic acid-mono- or-di-C₁-C₄-alkylamino-C₂-C₄-alkyl esters and salts thereof, acrylic orC₁-C₄-alkylacrylic acid-hydroxy-C₂-C₄-alkyl esters, acrylic orC₁-C₄-alkylacrylic acid-(C₁-C₄-alkyl)₃silyloxy-C₂-C₄-alkyl esters,acrylic or C₁-C₄-alkylacrylic acid-(C₁-C₄-alkyl)₃silyl-C₂-C₄-alkylesters, acrylic or C₁-C₄-alkylacrylic acid-heterocyclyl-C₂-C₄-alkylesters and salts thereof, C₁-C₂₄-alkoxylated poly-C₂-C₄-alkylene glycolacrylic or C₁-C₄-alkylacrylic acid esters, acrylic orC₁-C₄-alkylacrylamides, acrylic or C₁-C₄-alkylacrylmono- or-di-C₁-C₄-alkylamides, acrylic orC₁-C₄-alkylacryl-di-C₁-C₄-alkylaminoC₂-C₄-alkylamides and salts thereof,acrylic or C₁-C₄-alkylacryl-amino-C₂-C₄alkylamides, acrylonitrile,methacrylonitrile, 4-aminostyrene and salts thereof,di-C₁-C₄-alkylaminostyrene and salts thereof, vinyl substitutedheterocycles, styrene sulfonic acid and salts, vinylbenzoeic acid andsalts, vinylformamide and amidosulfonic acid derivatives.
 8. Acomposition according to claim 1 wherein the polymer blocks A or B orboth are reaction products with reactive polar monomers selected fromthe group consisting of glycidyl acrylic or C₁-C₄-alkylacrylic acidesters, 2-isocyanatoethyl acrylic or C₁-C₄-alkylacrylic acid esters andC₃-C₈-alkyl- or C₃-C₈-alkenyl-dicarboxylic acid anhydrides.
 9. Acomposition according to claim 1 wherein the dispersible organic pigmentparticles of component b) are selected from the azo pigment groupconsisting of azo, disazo, naphthol, benzimidazolone, azo condensation,metal complex, isoindolinone, isoindoline, chinophthalon and dioxazinepigments and the polycyclic pigment group consisting of indigo,thioindigo, quinacridones, phthalocyanines, perylenes, perionones,anthraquinones, anthrapyrimidines, indanthrones, flavanthrones,pyranthrones, anthantrones, isoviolanthrones, diketoypyrrolopyrroles,carbazoles and pearlescent flakes.
 10. A composition according to claim1 wherein the dispersible inorganic pigment particles of component b)are selected from the group consisting of aluminum, aluminum oxide,silicon oxide, silicates, iron(III) oxide, chromium(III) oxide,titanium(IV) oxide, zirconium(IV) oxide, zinc oxide, zinc sulfide, zincphosphate, mixed metal oxide phosphates, molybdenum sulfide, cadmiumsulfide, carbon black, graphite, vanadates, chromates, molybdates, andmixtures or crystal forms thereof.
 11. A composition according to claim1 which additionally contains binding agents and conventional additives.12. A composition according to claim 1 1 wherein the conventionaladditives are selected from the group consisting of surfactants,stabilizers, anti-foaming agents, dyes, plasticizers, thixotropicagents, drying catalysts, anti-skinning agents and leveling agents. 13.A composition according to claim 1 comprising a) 0.1-99.9% by weight ofa block copolymer (I), wherein In, X, p and q are as defined in claim 1;A represents a polymer block consisting of repeating units of acrylic ormethacrylic acid-C₁-C₂₄-alkyl esters; B represents a polymer blockconsisting of repeating units of acrylic or methacrylicacid-C₁-C₂₄-alkyl esters which are copolymerized with at least 50% byweight of monomers carrying functional groups and wherein the monomersare selected from the group consisting of acrylic or methacrylic acidand salts thereof, acrylic or methacrylic acid-mono- or-di-C₁-C₄-alkylamino-C₂-C₄-alkyl esters and salts thereof, acrylic ormethacrylic acid-hydroxy-C₂-C₄-alkyl esters, acrylic or methacrylamide,acrylic or methacrylic-mono- or -di-C₁-C₄-alkylamides, acrylic ormethacryl-amino-C₂-C₄alkylamides, and vinyl substituted heterocyclesselected from the group consisting of vinylpyrrolidone, vinylimidazoleor salts thereof and vinylcarbazole; x and y represent numerals greaterthan zero and define the number of monomer repeating units in A and B;and X represents a polymer chain terminal group; and b) 0.1-99.9% byweight of dispersible pigment particles.
 14. A pigment dispersioncomprising a dispersed phase consisting of a) a block copolymer of theformula I, wherein In, A, B, X, x, y, p and q are as defined in claim 1;and b) dispersed pigment particles; and a liquid carrier selected fromthe group consisting of water, organic solvents and mixtures thereof.15. A process for preparing a composition according to claim 1, whichcomprises copolymerizing by atom transfer radical polymerization (ATRP)fragments A and B in the presence of polymerization initiator

wherein In, p and q are as defined in claim 1, and X represents Halogenand a catalytically effective amount of a catalyst capable of activatingcontrolled atomic radical polymerization, replacing halogen X with adifferent polymer chain terminal group X′ and adding dispersible pigmentparticles and optionally binder materials, fillers or other conventionaladditives.
 16. A process for preparing a pigment dispersion compositonaccording to claim 1 which comprises dispersing in a liquid carrier thepigment particles in the presence of the block copolymer of the formulaI, wherein In, A, B, X, x, y, p and q are as defined in claim
 1. 17. Amethod for preparing coating compositions, prints, images, inks orlacquers which comprises incorporating the pigment dispersion accordingto claim 1 therein.
 18. A coating composition which comprises 0.01-10parts by weight of a pigment dispersion composition according to claim 1per 100 parts by weight of a solid film-forming binder.
 19. A processfor preparing a coating composition according to claim 18 whichcomprises combining the pigment dispersion composition with thefilm-forming binder.